1. Field of the Invention
The present invention relates to a method of manufacturing a liquid jet head, a method of manufacturing a piezoelectric element, and a liquid jet apparatus.
2. Description of Related Art
A piezoelectric element used for a liquid jet head or the like is an element in which a dielectric film made of a piezoelectric material having an electro-mechanical transduction function is interposed between two electrodes. For example, the dielectric film is made of a crystallized piezoelectric ceramics. Such a piezoelectric element is used as pressure generating means for ejecting a liquid from nozzle openings of a liquid jet head.
A method of manufacturing the piezoelectric element includes forming a lower electrode film on one surface of a substrate (a flow passage forming substrate) by a sputtering method, forming a piezoelectric layer on the lower electrode film by a sol-gel method or an MOD method, forming an upper electrode film on the piezoelectric layer by a sputtering method, and patterning the piezoelectric layer and the upper electrode film to from the piezoelectric element.
When the piezoelectric layer is formed, application of an application solution to be turned into a piezoelectric precursor film on the substrate is performed by a spin coating method.
Here, when the application solution to be turned into the piezoelectric precursor film is applied onto a flow passage forming substrate wafer by the spin coating method, the plurality of piezoelectric films are laminated on each of the flow passage forming substrate wafers by repeatedly performing a process of applying the application solution onto each of the flow passage forming substrate wafers of a flow passage forming substrate wafer group, which is constituted by the plurality of flow passage forming substrate wafers, to form one layer and a process of drying the application solution to form the piezoelectric precursor film. That is, after a first piezoelectric precursor film is formed on each of the flow passage forming substrate wafers, a second piezoelectric precursor film is sequentially formed on each of the flow passage forming substrate wafers.
However, a problem may occurs in that a deviation is caused in displacement characteristics of the piezoelectric element due to occurrence of a difference in the thickness of the applied application solution between the plurality of flow passage forming substrate wafers and occurrence of a difference in the thickness of the piezoelectric element formed by laminating the piezoelectric films between the flow passage forming substrate wafers.
Moreover, a problem may occur in that the deviation is caused in the displacement characteristics of the piezoelectric element due to occurrence of the difference in the thickness of the application solution applied in an in-plane direction of the flow passage forming substrate wafer when the application solution to be turned into the piezoelectric precursor film is applied onto the flow passage forming substrate wafers by the spin coating method and due to occurrence of the difference in the thickness of the piezoelectric elements formed by laminating the piezoelectric films.
Due to the difference in the displacement characteristics of the piezoelectric element, a problem may occur in that a difference occurs in liquid ejection characteristics of each liquid jet head when the liquid jet heads each having one chip size are formed by dividing the flow passage forming wafer. Moreover, a problem may also occur in that the liquid ejection characteristics cannot be obtained when the plurality of liquid jet heads are mounted on a liquid jet apparatus for use.
Moreover, these problems occur not only in the method of manufacturing the liquid jet head having the piezoelectric elements but also in a method of manufacturing a piezoelectric element used for other devices.